package JavaTransaction;

import java.rmi.*;

/** 
 * Distributed Transaction System in Java.
 * 
 * failure reporting is done using two pieces, exceptions and boolean 
 * return values.  Exceptions are used for systemy things - like 
 * transactions that were forced to abort, or don't exist.  Return
 * values are used for operations that would affect the consistency
 * of the database, like the deletion of more cars than the database
 * knows about.    
 * If there is a boolean return value and you're not sure how it 
 * would be used in your implementation, ignore it.  I used boolean
 * return values in the interface generously to allow flexibility in 
 * implementation.  But don't forget to return true when the operation
 * has succeeded.
 */

public interface ResourceManager extends Remote {
	/**
	* Start transaction.
	*
	* @return a unique transaction ID.
  */
	public int start() throws RemoteException; // returns Xid
	/**
	* Commit transaction.
	*
	* @return success. 
  */
	public boolean commit(int transactionId) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 
	/**
	* Abort transaction.
	*
	* @return nothing, but this may change.
  */
	public void abort(int transactionId) 
		throws RemoteException, 
			InvalidTransactionException; 

	// administrative interface
	/**
	* Add seats to a flight.  In general this will be used to create a new
  * flight, but it should be possible to add seats to an existing flight.
	* Adding to an existing flight should overwrite the current price of the
	* available seats.
	*
	* @return success.
  */
	public boolean addFlight(int Xid, int flightNum, int flightPrice, int flightSeats) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 
	/**
	* Delete the entire flight.
	*  deleteflight implies whole deletion of the flight.  
	*   all seats, all reservations.  It's undecided what will happen
	*   if a customer has a reservation on this flight, but one possibility
  *   is to delete the customer as well.  The other possibility is to 
  *   return failure.
	*
	* @return success.
  */
	public boolean deleteFlight(int Xid, int flightNum) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 
		
  /** Add rooms to a location.  
	* This should look a lot like addFlight, only keyed on a string location
  * instead of a flight number.
  */
	public boolean addRooms(int Xid, String location, int numRooms, int price) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 
  /** Delete Rooms from a location.
  * This subtracts from the available room count without allocating the 
  * rooms to a customer.  It should fail if it would make the count of
  * available rooms negative.
  *
  * @return success
  */
	public boolean deleteRooms(int Xid, String location, int numRooms) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 

  /** Addition and deletion of cars.
  * Cars have the same semantics as hotels.
  */
	public boolean addCars(int Xid, String location, int numCars, int price) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 
	public boolean deleteCars(int Xid, String location, int numCars) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 

	// technical/testing interface
	/** Shutdown gracefully.
  * When this RM restarts, it should not attempt to recover its state if
  * the client called shutdown to terminate it.
  * @return success
  */
	public boolean shutdown() 
		throws RemoteException;
	/** Call exit after a specified number of disk writes.
  * Support for this method requires a wrapper around the system's 
	* write to disk command that decrements the counter set by this method.
	* This counter should default to 0, which implies that the wrapper
	* will do nothing.  If the count is non-zero, the wrapper should decrement
  * the counter, see if it becomes zero, and if so, call exit(), otherwise
  * continue the write.
  *
  * This method is not part of a transaction.
  *
	* @return success
  */
	public boolean selfDestruct(int diskWritesToWait) 
		throws RemoteException;

	// query interface.
	/* queryFlight returns the number of empty seats. */
	public int queryFlight(int Xid, int flightNumber) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 
	public int queryFlightPrice(int Xid, int flightNumber) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 
	/* return the number of rooms available at a location */
	public int queryRooms(int Xid, String location) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 
	public int queryRoomsPrice(int Xid, String location) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 
	/* return the number of cars available at a location */
	public int queryCars(int Xid, String location) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 
	public int queryCarsPrice(int Xid, String location) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 
  /* return a bill */
	public String queryCustomerInfo(int customer) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 

  // customer functions
  /* new customer just returns a unique customer identifier */
  public int newCustomer(int Xid) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 
	/* deleteCustomer removes the customer and associated reservations */
  public boolean deleteCustomer(int Xid,int customer) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 
  public boolean reserveFlight(int Xid, int customer, int flightNumber) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 
  public boolean reserveCar(int Xid, int customer, String location) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 
  public boolean reserveRoom(int Xid, int customer, String location) 
		throws RemoteException, 
			TransactionAbortedException,
			InvalidTransactionException; 
}